Balancing centrifugal machine



Feb. 15, 1949. T. H. REID 2,461,773

BALANCING CENTRIFUGAL MACHINE Filed June 11, 1945 $0M! M5744 2511/01/5050M! All-Z44 REMOVED Fae Mum-m5 PuzPoSi-S F02 amwa/va puefiosas JNVENTOR. 7/70/1445 A. 25/0 Patented Feb. 15, 1949 UNITED STATES ATNT OFFICE1 Claim.

This invention relates to the balancing of rotating devices and morespecifically to the balancingof centrifugal machines used in themanufacture of sugar.

An object of this invention is to provide novel and improved means forbalancing the rotating baskets of sugar centrifugal machines.

In modern sugar refinery practice, the centrifugal machines employed forpurgin crystalline sugar of mother liquor or the like are insubstantially continual operation. The basket'of each machine is loadedwith a charge of sugar magma or massecuite, accelerated rapidly to highspeed, and, after a few minutes, rapidly braked and unloaded inpreparation for the next charge. It is very important that these basketsbe very accurately balanced or the centrifugal force acting on theunbalanced mass will in time cause the machine to be torn to pieces. Inlow speed centrifugal machines, this balancing can be accomplished bysoldering or welding small pieces of metal on the periphery of thebasket (usually between adjacent reinforcing hoops surrounding thebasket). In a high speed machine, however, such as that which employs abasket of the type disclosed in Patent 2,315,980 issued April 6, 1943 toCharles A. Olcott, for example, this means of balancing cannot be usedas the small bits of metal fly off at the high speed. The presentinvention relates to means for baancing high speed sugar centrifugalmachines which does not involve addin extra material.

In accordance with a specific illustrative embodiment ofthe presentinvention, this balancing is attained by the-enlargement of at least theouter ends of certain of the apertures in the basket through which theliquids are ejected. The apertures in a basket are usually arranged inrings, with the holes in alternate rings preferably staggered so thatthe entire wall of the basket is covered with perforations. In thebasket disclosed in the above-mentioned Olcott patent, externalcircumferential grooves are cut in the basket wall, each grooveoverlying and passing through one of the rings of holes. In order toprovide maximum strength near the top and bottom of the basket where theshearin stresses are greatest, at least one of the rings of holesnearest the respective top and bottom basket heads is left ungrooved.These latter holes are usually flared as it has been found thatcentrifuged ma- It has been discovered that small bits of metal can beeasily removed from certain ones of the flared holes in the upper andlower parts of the centrifugal wall, preferably by countersinking-orincreasing the flare, and that this removal of certain weight on oneside or one portion of the basket can be used to effect balancing of thecentrifugal ma chine. In cases where the holes are not flared, eithercountersinking or reaming can be used.

The invention will be more readily understood by referrin to thefollowing description taken in connection with the accompanying drawingforming a part thereof, in which:

Fig. 1 is an elevation view, partly in cross-section, of a portion of asugar centrifugal showing a basket which is balanced in accordance withthe invention;

Fig. 2 is a horizontal cross-sectional view of a portion of theperiphery of the basket of Fig. 1 showing certain holes in the basketcountersunk to remove metal for balancing purposes; and

Fig. 3 is a horizontal cross-sectional view of a portion or" theperiphery of the basket of Fig. 1 showing certain holes in the basketreamed to remove metal for balancing purposes.

Referrin more specifically to the drawing, Fig. 1 shows, by way ofexample for illustrative purposes, a sugar centrifugal machine I53 whichis balanced in accordance with the invention. The machine it! includes avertically arranged spindle ll driven by any suitable means (not shown),such as by a separate hydrauic or electric motor or by pulleys orgearing from a source of power common to a plurality of such centrifugalmachines, and a basket it supported from the spin dle and adapted'toturn therewith within a casing it. The casing is so shaped and arrangedin well known manner that mother liquor, wash .water and the likeexpelled through the foraminate wall of the basket flows down the innerface or curb of the easing into an annular trough M where it iscollected and drawn off.

.The basket 12 comprises a cylindrical wall I5, an upper head iiicomprising an'integral annular flange and a corresponding lower head I?of similar construction. This integral structure is preferably forgedfrom a single ierced billet of steel and machined to final dimensions.To the lower head H is welded a steel hub it that is fitted to spindle Hand firmly fastened thereto by any suitable means. The welded joint 19lies in a region where the stresses incident to high speed operation arecomparatively small.

The cylindrical wall l5 of the basket l2 has numerous holes 20 for theescape of centrifuged molasses or the like. These are arranged in amultiplicity of circumferential rings of holes with the holes inalternate rings preferably staggered as in the arrangement shown in thedrawing, so that the entire wall is pierced by perforations. As aspecific instance of practice which may be borne in mind for betterunderstanding of the invention, the inside diameter of the basket may beforty inches, its height twenty-four inches, and the holes one-quarterinch in. diameter where the metal is to be removed. By graduallyenlarging certain of the holes 22 and by rotating spaced apart one inchon centers in each ring with the rings one inch apart. As disclosed inthe above-mentioned Olcott patent and as shown in the drawing, externalcircumferential grooves 2| are cut in the basket wall, each grooveoverlying and passing through one of the rings of holes. tangularcross-section but rounded at the bottom The grooves 2| are preferablyof. recor at the bottom corners, and the width of each forth above,,thegroove width may be one quarter of: an inch. As pointed out in theOlcott patent,-'the portions in the rings between the holes contributevery little to holding the basket together. and hence they are reducedin vmass (by grooving them) and therefore develop less cen- Y trifugalforce to burden adjoining portions without a corresponding loss instrength. The present-invention, however, is preferably not concernedwith the apertures20 in the grooved rings 2! but in the apertures 22which are arranged in ungrooved rings in the upper and lower portions ofthe basket wall. These portions of the wall are left ungrooved so thatshearing forces, which are greatest at top and bottom, can be betterresisted. These holes 22' may already be tapered or countersunk as shownin Fig. 2 and small additional bits of metal are removed from certainones of the holes 22 by countersinkingwhen it is determined that themass on the side nearest these certain holes is larger than it should befor perfect balancing. This can be determined by rotating the basket athigh speeds on a machine called a dynamic balancer several makes ofwhich are on the market.

The holes 22 to be enlarged are in general only: atone side of thebasket, at either the top or. the bottom. This is caused by the factthat slight errors in machining or density of the metal generally-result in the basket being heavier on one side .than on the other(which would tend to make the machine run out of balance were it notcorrected.) In dynamic balancing it is necesside. In short, tobalancethe basket, metal must beremoved at the proper, place and in the properamounts. The

a dynamic balancer." indicates,

the machine after each enlargement, it can be determined when themachine is perfectly balanced.

As an alternative to countersinking, the outer ends of certain holes 22can be reamed out, as shown in Fig. 3. This means'can be used eitherwith tapered or untapered holes.

The means of "balancing describedabove has the advantages that (1) thereare no parts to fiy off at high speeds, (2) no new holes need bedrilled, use being made of holes already having a function,-and-y(3)-the enlargement of the holes takes very little time and is simple andinexpens1ve.--

It will .be, apparent that although the present invention has beendescribed with reference to itspreferred embodiments it will beunderstood that it is capable of embodiment, in a variety of;:other:fo'rms;.within the. spirit and scope ofthe claim, and that the specificproportions vand; dimensions hereinbefore set forth are illustrative andnot limitative. While it is preferredithat the 1 apertures which areenlarged; for. balancing purposes .be near :the vertical extremities'(topzand bottom) of the basket, it will be readily apparent .J.

that'they need, not be solocated;

What issclaimed is:.

A basket for. a sugar centrifugal; which is nor-- mal-ly slightly but ofbalance comprising a bottom'memberyanuppenhead member and. a'cylindricalwall therebetweem'said wall having a cen- A tralportion. with la:plurality of tgroovedrings therearoundand :upper. and lower portionsadjacent the head member and bottom: member, re-

the said basket is balanced, said certain 'ones be-' ing .on'the side:of said basket which would be the heavy side'when it is rotating wereit not for:

the said-removal of metal';

THOMAS H. REID.

REFERENCES CITED The following references are of record in the file 'ofthis patent:

UNITED STATES PATENTS Number Name Date 1,189,726' Nyberg July 4, 1916';1,195,074 Ohlsen Aug915, 1916. 2,068,636 Roberts Jan. 19, 1937 2,315,980Olcott Apr. '6, 1943';

